This invention is directed to a method and apparatus which reduces fuel consumption under certain engine operating conditions and simultaneously reduces automobile exhaust emissions and, more particularly, to a device which shuts off a carburetor idle fuel passage during deceleration conditions.
A significant emphasis has been made in the past two decades to reduce automobile exhaust emission pollution. While the problem of exhaust pollution has been noted at least as early as 1946 (U.S. Pat. No. 2,466,090), by 1960 automobiles were equipped with PCV devices to redirect crankcase fumes into the combustion chambers. By 1966, the government of California required that exhaust emission pollution from automobiles be reduced to certain levels. Subsequently, the automobile manufacturers have continued to reduce automobile exhaust pollution, primarily as a result of various laws and regulations.
Partially as a result of certain techniques used by the automotive industry in the reduction of exhaust pollution, fuel efficiency has declined during a time when fuel resources were becoming increasingly scarce. Thus, attempts were made to redesign vehicles to obtain increased efficiency. For example as early as the 1971 model year, the largest U.S. automobile manufacturer substantially increased the fuel tank size in most of its larger vehicles. While this did not have any positive effect on efficiency, it nearly halved the frequency of fuel stops required to operate a car with a particular fuel reserve, giving the purchaser the illusion of satisfactory fuel efficiency.